Heater



June 26, 1945.l H. J. DE N. MCCQLLUM HEATER 3 Sheets-Sheet lA Filed Ded. 18, 1943 June 26, 1945- H. J. DE N. MccoLLuM 2,379,018

HEATER Filed Dec. 18, 1943 5 Sheets-Sheet 5 'till .....fltll lll Patente .lune 26, i945 'rea i Henry i. Ane N. McCollum McCollum, deceased McCollum, Chicago, executrix oi said Henry J. De N.

lll.; Thelma- I Application December 18, 1943, Serial No. 514,755 A2 Claims.- (Cl. 126-102) My invention relates ,'generally." to heaters and more particularly to heaters oi" the sealed combastion type incorporatinga novel form of heat I exchanger.

.it is an object of my invention to provide an improved heater of the sealed combustion type having a simple and efficient heat exchanger,

, which is suitable for use in heating aircraft and which may be economically manufactured a further object is to provide an improved heat exchanger having primary heat transfer surfaces of large area and which may be manufactured by simple manufacturing processes.

'A further object is to provide an improved heat exchanger which is light in Iweight and which, while made of thin sheet metal, is rigid and durable.

Other objects will appear from the following description, reference being had to the accompanying drawingsin which;l v j Fig. l is a central longitudinal sectional View y taken on the line l-i of Fig. 2;

Fig. 2 is a transverse sectional view taken on` the line 2-2 of Fig. l; and

Fig'. 3 is a transverse the line: 3-3 of Fig. 1.

The heater comprisesa sheet metal hollow cylinder lll having a combustion air preheating tubel l2 extending longitudinally. therethrough ,w and supported by anged annular heads It and l5. A narrow annular baille it is secured in the cylinder ill latter into a vprimary combustion chamber` I8 and a secondary combustion space 20. The tube l2 is provided with rows of perforations 22 permit 'limited now of air into the secondary combustion space 2t.

The air for primary combustion -ows through the full length oi the tube i2. The latter has a bend ze formed integrally therewith-and is secured to the heater casing 2S and to a pipe 28 by a suitable flanged connection 3d; The -pipe sectional view taken on' and divides the space within the housing M which lll. A. hot wire electrical igniter 46 of conventional construction is arranged to ignite that portion of the combustible mixturewhich, due to centrifugal action, tends to enter the igniter housing through port i2 and ow therefrom through port't. The supply of energizing cury rent' for the igniter d6 may be controlled by 'any' v switch completed circuit so as to be de-energized when the heater well lsnown thermostatic attains its operating temperature.

The heat' exchanger comprises a plurality of pairs .of generally cylindrical sheets Sli-5l, 52-53, 54--55, and 56-57. The sheet ihas an elongated port 60 which registers with a similar port 6l formed in the cylinder l0, and is seam weldedto the cylinder Il! around the ports 60, 6l so as to be air-tight..

In the manufacture of the heat exchanger by one method which may be employed, the sheet 5l may then be placed over the'sheet 5|) and the offset end edges of the two sheets then' seam welded together to form two passageways 62, 63 (Fig. 3) for the iiow of the products of combus tiony from the ports 60, 6I to a similar port St formed by registering openings in the sheets 5l and 52, these sheets being seam welded together 'around the port 64.

In a similar manner sheet 53 is secured .to sheet 66, and sheet 55 is secured to alport 68. Sheet 51 .is welded 54 aroundv a port sheet 55 around to the casing 26 around an exhaust port 10, and

it is connected to a carburetor 32, which includes f a neat bowl @il and a. solenoid operated iuel valve Fuei is supplied to the carburetor through a `tube tt. Y

e The combustible mixture ci fuel and air supplied by the carburetor is conveyed to the primary combustion chamber it through an induction tube Lit. The end of the tube fili within the combusti'on chamber has a bend to impart a swirling 'motion to the mixture, as best shown in Fig. 2.

The cylinder l@ has a pair of elongated ports d2, llt'iormed therein, these ports communicating with suitable passageways formed in an isniter a suitable thimble 12, for connection exhaust pipe, is welded to the casing 26.

By virtue of this arrangement of the sheets Sti-5l, the products of combustion will iiow from the cylinder l@ to the exhaust port 'l0 in the directions indicated by the arrows in Fig.- 3i' The ow is enectively through two passageways of narrow rectangular cross section, these passageways being jointed at intervals, at the ports 6i, te, et and l0. Because of this arrangement the products of combustion will flow equally through with an the two alternative paths provided between the f Successive ports S--tL Si, 66,' tand l0, and the temperature gradients along the two alternative paths will be substantially the same.

In the construction illustrated, the successive pairs 0f sheets 50-57 arelequally graduated in diameter so that sheets 52-53 and 5B-5l are concentric with the cylinder l0, VWhile sheets 5ft-5l, `56-55. and the casing 26 are eccentric.

with respect to the-cylinder le.

Suitable brackets it may be provided to am in maybe welded to the cylindery supporting heat exchanger assembly in the casing 2l.

The heater may have its air for combustion and the ventilating air supplied by a ram or scoop connected to a shroud 1l secured to the casing 2l. 'I'he ventilating air flows fiongitudinally through the crescent-shaped passageways formed embodiment of the invention, it will be apparent to those skilled in the art that the underlying principles thereof may be employed in variations and modifications of the apparatus disclosed. I

therefore desire by the following claims to include r within the scope of my invention all such modifications and variations by'which substantially the results of the invention may be obtained by the l use of substantially the same or equivalent means.

I claim:

l. A heater comprising' a central cylinderv forming a combustion space, means to supply a fuel and air for combustion to said space, and a plurality of pairs of cylindrical sheets surrounding said cylinder, each pair of sheets being joined at their ends and spaced to provide a passageway between them, and alternate pairs of said sheets being eccentrically arranged and tangentially joined tothe intermediate pairs of sheets and to said cylinder, said sheets-having registering ports at'the places at which they are joined, thereby to provide a closed path for the flow of the products of combustion from said cylinder to the outermost pair of said sheets, with the spaces intermediate thepairs of sheets and said cylinder forming passageways for the ilow lof ventilating air in a directionlongitudinally oiysaid cylinder.

2.- A heat exchanger comprising a plurality of l pairs of cylindrical sheets surrounding one another and of progressively increasing diameters, each pair of sheets being joined at their ends and spaced to provide a passageway between them, and alternate pairs of said sheets being eccentrically arranged and tangentially joined to the intermediate pairs of sheets, said sheets having registering ports at the places -at which they are joined, thereby to provide a closed path for the flow of one fluid from the innermost to the outermost pair of said sheets, with thev spaces' intermediate the pairs of sheets forming passageways for the flow of another iluid in a direction longitudinally of said cylindrical sheets.

HENRY J. DE N. t/Lcconmm.l 

